Method and system for removing a liquid from a container for accommodating an ophthalmic lens

ABSTRACT

A method of removing a liquid from a container ( 1 ) for accommodating an ophthalmic contact lens, in particular a soft contact lens, during transporting the container ( 1 ) from a liquid bath ( 13 ) to a subsequent processing station ( 14 ), the method including the steps of:
         transporting the container ( 1 ) from the liquid bath to the subsequent processing station,   generating suction ( 20 ), and   applying the suction ( 20 ) to a bottom ( 11 ) of the container ( 1 ) during the step of transporting the container ( 1 ) from the liquid bath to the subsequent processing station, thereby removing the liquid from the container ( 1 ).

This application is a Divisional of U.S. patent application Ser. No.15/350,374, filed Nov. 14, 2016, which claims the benefit under 35 USC119(e) of U.S. provisional application Ser. No. 62/266,034 filed on Dec.11, 2015, the contents of each of which are incorporated herein byreference in their entireties.

FIELD OF THE INVENTION

The present invention relates to a method and a system for removing aliquid from a container for accommodating an ophthalmic lens, inparticular a contact lens such as a soft contact lens.

BACKGROUND OF THE INVENTION

Contact lenses, particularly soft contact lenses, are generallymanufactured in automated production processes well-known in the art.Depending on the lens forming materials used and also depending on themethod of manufacturing, the contact lenses have to be immersed invarious liquids such as extraction liquids, rinsing liquids, coatingliquids, etc., to obtain the final contact lens which is suitable to beworn in direct contact with the wearer's eye. For that purpose, it isknown to transport the contact lenses through several baths containingsuch liquids. For example, the contact lenses are introduced intocontainers arranged in a transport carrier which is moved along thelength of the individual baths such that the contact lenses contained inthe respective containers are exposed to the liquids of the respectivebaths. For example, after having been transported through one liquidbath the containers arranged in the transport carrier are transferred toa further liquid bath containing a further liquid. By way of example,the liquid baths may serve for lens rinsing, extraction, or coatingpurposes and may contain either the same kind of liquid, if necessary indifferent concentrations, or may contain liquids of different kind whichare used for different purposes (see above).

US 2011/091642 A1 describes a method and apparatus for transportingcontact lenses accommodated in respective containers throughsuccessively arranged treatment baths comprising an automaticallyoperating transfer means for transferring the carriers from one dippingbath to the next dipping bath along the travel path.

US 2011/0089053 A1 discloses a container for the accommodation of acontact lens during lens treatment processes such as extraction and/orrinsing and/or coating processes. The container may either be molded inone piece or may comprise several individual pieces which are assembledto form a container. The container generally comprises an elongatedtubular body and, at a distal and of the container, a bottom whichprotrudes convexly towards the outside of the container. The bottom isprovided with a number of apertures which enable a flow of liquid intoand out of the tubular body.

Once the container has reached the end of the respective bath, thecontainer is lifted out of the liquid of the liquid bath for beingtransferred into the liquid of the subsequent liquid bath, or for beingtransferred to another subsequent processing station. During thistransfer, liquid of the preceding liquid bath may remain adhered to thesurface of the bottom of the container and on the contact lens itselfaccommodated in the container, and such liquid may either be carriedover to the subsequent liquid bath or may be spilled in the productionarea. In case the container is transferred to a subsequent liquid bath,the corresponding liquid in the said subsequent liquid bath either maybe of the same kind but may have a concentration that differs from theconcentration of the liquid contained in the preceding bath, or thesubsequent bath may contain a liquid of a different kind. Accordingly,the carry-over of liquid from the preceding bath may either change theconcentration of the liquid in the subsequent liquid bath or maycontaminate the liquid in the subsequent liquid bath. In the first case(subsequent liquid bath contains the same kind of liquid at differentconcentration), the concentration of the liquid of the subsequent liquidbath must be monitored and may have to be maintained through theaddition of fresh liquid or through the addition of one or more of theconstituents of the liquid. In the other case (subsequent liquid bathcontains different kind of liquid), the liquid of the subsequent liquidbath may have to undergo complex purification or may have to be replacedin case the concentration of the “contaminant” in the subsequent liquidbath exceeds a predefined threshold concentration.

For example, prior to immersing the contact lenses in an extractionliquid, they are rinsed in a water bath. The rinsing of the contactlenses in water prevents or reduces the soiling of the extractionliquid. However, as the containers containing the contact lenses aretransferred from the water bath to the extraction liquid bath, smallamounts of water are carried over from the water bath to the extractionliquid bath. As a consequence, during the production of contact lensesthe concentration of the extraction liquid bath is constantly reduced,so that after a certain time the extraction liquid bath must be purifiedor the “contaminated” extraction liquid must be replaced with freshextraction liquid.

It is therefore an object of the invention to further improve theefficiency of the treatment of ophthalmic lenses such as contact lenses,in particular soft contact lenses, in liquid baths.

SUMMARY OF THE INVENTION

To achieve these objects, the present invention suggests a method and asystem as specified by the features of the respective independentclaims. Advantageous aspects of the method and system according to theinvention are the subject of the dependent claims.

As regards the method, a method of removing a liquid from a containerfor accommodating an ophthalmic contact lens, in particular a contactlens such as a soft contact lens, during transporting the container froma liquid bath to a subsequent processing station is suggested. Themethod comprises the steps of:

-   -   transporting the container from the liquid bath to the        subsequent processing station,    -   generating suction, and    -   applying the suction to a bottom of the container during the        step of transporting the container from the liquid bath to the        subsequent processing station, thereby removing the liquid from        the container.

According to one aspect of the method according to the invention, thestep of applying suction comprises

-   -   providing an aspirator comprising a suction cup having a concave        wall with at least one suction orifice arranged in the concave        wall,    -   applying the suction through the at least one suction orifice        arranged in the concave wall of the suction cup, and    -   moving the suction cup towards the bottom of the container with        the concave wall of the suction cup facing the bottom of the        container.

According to a further aspect of the method according to the invention,the bottom of the container has a convex shape, and the concave wall ofthe suction cup has a shape which corresponds to the convex shape of thebottom of the container.

According to still a further aspect of the method according to theinvention, applying the suction to the bottom of the container allows aleakage stream to flow between the bottom of the container and theconcave wall of the suction cup towards the at least one suction orificein the concave wall of the suction cup.

According to yet a further aspect of the method according to theinvention, the suction cup is moved towards the bottom of the containeronly to an extent that the suction cup does not contact the bottom ofthe container.

Still in accordance with a further aspect of the method according to theinvention, the suction is applied to the bottom of the container duringa time period in the range of 0.5 seconds to 2 seconds.

In particular, the air flow of the suction is in the range of from 2 m³to 8 m³.

In a further aspect of the invention, the suction (underpressure) is inthe range of up to 900 hPa (corresponding to 900 millibars), inparticular in the range of 350 hPa to 750 hPa (corresponding to 350millibars to 750 millibars).

In accordance with another aspect of the method according to theinvention, the transport of the container from the liquid bath to thesubsequent processing station is accomplished intermittently, and thesuction is applied to the bottom of the container at the time thetransport of the container is intermitted.

The term “intermittently” is to be understood in a sense that thetransport of the containers is performed such that there are timeperiods in which the container is transported (moved) along the travelpath and time periods where this transport of the container along thetravel path is intermitted (interrupted).

As regards the system for removing a liquid from a container foraccommodating an ophthalmic contact lens, in particular a soft contactlens, the system according to the invention comprises:

-   -   a transport carrier comprising a container having a bottom,    -   a conveyor for transporting the transport carrier from a liquid        bath to a subsequent processing station,    -   an aspirator comprising a suction cup connected to a vacuum        supply line, for applying suction to the bottom of the        container, and    -   a positioner for arranging the container relative to the suction        cup such that the bottom of the container is exposed to the        suction applied by the suction cup during operation, in order to        remove the liquid from the container.

According to one aspect of the system according to the invention, thebottom of the container has a convex shape, and the suction cup of theaspirator has a concave wall with at least one suction orifice arrangedin the concave wall. The convex shape of the bottom of the container andthe shape of the concave wall of the suction cup correspond to allow foraccommodating the convexly shaped bottom of the container in a cavitybounded by the concave wall of the suction cup.

According to a further aspect of the system according to the invention,the positioner comprises an actuator for linearly moving the suction cupof the aspirator towards and away from the bottom of the container.

According to one aspect of the system according to the invention, theactuator is a pneumatic linear drive.

The method according to the invention allows for more efficienttreatment of the ophthalmic lens in the liquid of the respective liquidbath, as either no or only very little carry-over of treatment liquidfrom the preceding treatment bath may occur. This is due to the removalof a liquid by applying the suction to the bottom of the containerduring the step of transporting the container from the first treatmentbath to the second treatment bath. As a result, contamination ordilution is prevented or at least very greatly reduced so that areplacement of purification of the treatment liquid in the treatmentbaths can be either prevented or very greatly reduced.

Using a suction cup which is connected to a vacuum supply line forremoving the remaining treatment liquid from a preceding treatment bathby moving the suction cup towards the bottom of the container allows forvery efficiently removing the liquid. In particular when the suction cuphas a shape which corresponds to the shape of the bottom of thecontainer for accommodating the bottom of the container, removing theremaining liquid is highly efficient.

Applying suction and at the same time allowing a leakage stream to flowbetween the convex bottom of the container and the concave wall of thesuction cup towards the suction orifice in the concave wall of thesuction cup assists in transporting away through the vacuum supply lineany liquid which may adhere to the bottom of the container or on thesurface of the lens. The liquid is drawn in through the at least onesuction orifice arranged in the concave wall of the suction cup withoutdamaging the contact lens accommodated in the container.

Keeping a small distance between the suction cup and the (typicallyconvex) bottom of the container allows for the leakage stream to flowbetween the bottom of the container and the concave wall of the suctioncup, thereby effectively removing any liquid adhering to the container.

The advantages of the system according to the invention and of thevarious aspects thereof correspond to those already discussed above inconnection with the various aspects of the method according to theinvention. Therefore, they are not reiterated here.

As used in the specification including the appended claims, the singularforms “a”, “an”, and “the” include the plural, unless the contextexplicitly dictates otherwise. When using the term “about” withreference to a particular numerical value or a range of values, this isto be understood in the sense that the particular numerical valuereferred to in connection with the “about” is included and explicitlydisclosed, unless the context clearly dictates otherwise. For example,if a range of “about” numerical value a to “about” numerical value b isdisclosed, this is to be understood to include and explicitly disclose arange of numerical value a to numerical value b. Also, whenever featuresare combined with the term “or”, the term “or” is to be understood toalso include “and” unless it is evident from the specification that theterm “or” must be understood as being exclusive.

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantageous aspects of the invention become apparent from thefollowing description of embodiments of the invention with the aid ofthe drawings, in which:

FIG. 1 is a cross-sectional perspective view of some essentialcomponents of an embodiment of the system according to the invention;

FIG. 2 is a cross-sectional view of some details of the system of FIG.1;

FIG. 3 is a detailed view of an arrangement of aspirators and suctioncups in a position spaced apart from one another (before or after liquidremoval);

FIG. 4 is a detailed view of the arrangement of aspirators and suctioncups of FIG. 3 in the operating position (during liquid removal);

FIG. 5 is an enlarged cross-sectional side view of the aspirator withthe suction cup in the spaced-apart position; and

FIG. 6 is an enlarged cross-sectional side view of the aspirator of FIG.5 with the suction cup in the operating position.

DETAILED DESCRIPTION OF EMBODIMENTS

As used in this specification, the term “liquid” or “treatment liquid”comprises any type of liquid to which the ophthalmic lens, in particulara contact lens such as a soft contact lens, may be exposed during acontact lens manufacturing process, and include in particular liquidsinfluencing the physical or chemical properties of the lens. Withoutbeing exhaustive, such treatment liquids may comprise extractionliquids, rinsing liquids, coating liquids or any other type of liquidand in particular also may comprise water.

FIG. 1 shows in cross-sectional perspective view some essentialcomponents of a system according to one embodiment of the invention. Ascan be seen from FIG. 1, the system comprises a plurality of containers1 each for accommodating a contact lens (not shown). The container 1enables a flow of a treatment liquid into and out of the container 1,and a plurality of transport carriers 12 holding the containers 1 duringconveyance through liquid baths 13, 14 (indicated by respective arrows)and during transfer from one liquid bath 13 (the preceding liquid bath)to another liquid bath 14 (the subsequent liquid bath), with thedirection of transport generally being from left to right in theembodiment shown in FIG. 1. The contact lenses (not shown) areindividually accommodated in the tube-like containers 1 which are heldside-by-side in the respective transport carriers 12 (see also FIG. 2).The transport carriers 12 are conveyed along a travel path through theliquid baths 13, 14 by a conveyor 3 including a conveyor chain. Fortransferring the transport carriers 12 from the preceding liquid bath 13to the subsequent liquid bath 14, the transport carriers 12 are liftedout of liquid bath 13 by conveyor 3 as shown in FIG. 1, are transportedhorizontally, and are then lowered again so that the containers 1carried by the respective carrier 12 are immersed in the liquid ofliquid bath 14 through which the carriers 12 are then transported. Thatportion of the respective container 1 (including at least a bottom 11 ofthe container 1) in which the contact lens is accommodated is completelyimmersed in the treatment liquid so that the contact lenses are exposedto the treatment liquid during the travel of the containers 1 throughthe respective liquid bath. Of course, instead of transporting thecontainers 1 from the preceding liquid bath 13 to the subsequent liquidbath 14, the containers could also be transported to a subsequentprocessing station other than a liquid bath. Thus, it is evident thatthe subsequent liquid bath 14 is one embodiment of a subsequentprocessing station.

The embodiment of the system shown in FIG. 1 further comprises aplurality of aspirators 2 (one for each individual container 1) having asuction cup 21 connected to a vacuum supply line 23 for applying suction20 (see FIG. 6) to the bottom 11 of the container 1. Suction cup 21 maybe formed by a solid, noncorrosive material like stainless steel or anadequate synthetic material. Also, the system comprises a positioner 4(see again FIG. 1) for moving the respective suction cup 21 towards thebottom 11 of the respective container 1 such that the bottom 11 of thecontainer 1 can be exposed to the suction 20 applied through the suctioncup 21 during operation (see FIG. 4), however, the respective suctioncup 21 is moved towards the respective container 1 only to an extentsuch that the suction cup 21 does not come into mechanical contact withthe bottom 11 of the container 1.

As discussed already further above, during transfer from the precedingliquid bath 13 to the subsequent liquid bath 14, a carry-over of liquidfrom the preceding liquid bath 13 to the subsequent liquid bath 14 mayresult either in a change in concentration of the liquid of thesubsequent liquid bath 14 (in case the subsequent liquid bath 14 is ofthe same kind), or may result in contamination of the liquid of thesubsequent liquid bath 14 (in case the subsequent bath is of a differentkind). In case of transportation of the containers 1 to a processingstation other than a subsequent liquid bath 14, the liquid carried overfrom the liquid bath 13 may get spilled in the manufacturing line whichis also unwanted.

To avoid such carry-over or spillage of liquid during the transport ofthe transport carrier 12 and the respective containers 1 from thepreceding liquid bath 13 to the subsequent liquid bath 14 (or otherprocessing station), the transport carrier 12 with the containers 1 isfirst arranged in a position relative to the aspirator 2 as is shown inFIG. 2 and FIG. 3, so that the bottom 11 of each individual container 1is arranged above a corresponding suction cup 21 of the respectiveaspirator 2. The suction cup 21 of the respective aspirator 2 is thenlifted towards the bottom 11 of the respective container 1 into aposition which is shown in FIG. 4,

As can be seen in FIG. 3 and FIG. 4, the aspirator 2 comprises a suctioncup 21 having a central suction orifice 24 in the center of a concavewall 22 of the suction cup 21 allowing to apply suction to the convexbottom 11 of the container 1. The concave wall 22 of the suction cup 21has a shape which corresponds to the convex shape of the bottom 11 ofthe container 1, so that the convexly shaped bottom 11 of the container1 is accommodated in a cavity bounded by the concave wall 22 of thesuction cup 21.

The positioner 4 comprises an actuator for linearly moving the suctioncup 21 from a retracted position (FIG. 3) towards the bottom 11 of thecontainer 1 until reaching a suction position (FIG. 4). This movementmay be performed with the aid of a pneumatic linear drive, which iscomprised by the positioner 4 shown in FIG. 1. This upward movement ofthe suction cup 21 is also indicated by the arrow shown in FIG. 5.

Once the suction cup 21 has been moved into the suction position, theconcave wall 22 of the suction cup 21 is arranged in the closed vicinityof the convex bottom 11 of the container 1 but does not contact thebottom 11 of the container 1. Rather, there is a small gap between theconcave wall 22 of the suction cup 21 and the convexly shaped bottom 11of the container 1 in order to allow for air to flow through that smallgap formed between the concave wall 22 of the suction cup 21 and theconvexly shaped bottom 11 of the container 1.

The small gap allows for a leakage stream of air to enter between theconcave wall 22 of the suction cup 21 and the convex bottom 11 of thecontainer 1. This leakage stream flows towards the central suctionorifice 24 in the concave wall 22 of the suction cup 21 and helps totransport liquid remaining on the surface of the bottom 11 of thecontainer 1 and on the contact lens away through the vacuum supply line23 through which the suction 20 is applied. However, the leakage streamand the suction applied are such that the remaining liquid isefficiently removed without affecting the contact lens accommodated inthe container 1.

In operation, the conveyor 3 conveys the transport carrier 12 from thepreceding liquid bath 13 to the subsequent liquid bath 14 (see FIG. 1).For that purpose, the transport carrier 12 with the containers 1 islifted out of the first liquid bath 13 and is conveyed to position abovethe aspirators 2. Once the transport carrier 12 has reached the positionabove the aspirators 2 (see FIG. 2 and FIG. 3), the transport of thecarrier 12 is intermitted (stopped), and the suction cups 21 are movedvertically towards the bottom 11 of the container 1 (see FIG. 5) intothe suction position, however, without contacting the bottom 11 of thecontainer 1 (see FIG. 4). Suction 20 is applied with the aid of a vacuumsupply line 23 through the suction orifice 24 arranged in the concavewall 22 of the suction cup 21, as this is shown in FIG. 6. Through theapplication of suction 20, an air stream air is drawn through the smallgap formed between the concave wall 22 of the suction cup 21 and theconvexly shaped bottom 11 of the container 1 into the suction orifice24.

By way of example only, the suction 20 may be applied to the bottom 11of the container 1 through the suction orifice 24 in the concave wall 22of the suction cup 21 during a time period in the range of 0.5 secondsto 2 seconds, at an air flow in the range of 2 m³ to 8 m³, and at asuction (underpressure) in the range of up to 900 hPa (corresponding to900 millibars), in particular in the range of 350 hPa to 750 hPa(corresponding to 350 millibars to 750 millibars).

Once removal of the liquid has been completed, the suction cups 21 arelowered again, and movement of the transport carrier 12 with thecontainers 1 accommodating the contact lenses towards and into thesubsequent liquid bath 14 is resumed. Through the afore-describedremoval of the liquid, any liquid adhering to the bottom 11 of thecontainer or to the contact lenses is reliably drawn in through thesuction orifice 24 together with the air stream, so that there is noliquid anymore that can be carried-over to the subsequent bath 14 orthat can be spilled.

It has already been mentioned above, that in the treatment process forcontact lenses a major contamination may arise during the conveyance ofthe container accommodating the contact lens between two liquid baths ofdifferent kinds. Therefore, it is advantageous to provide for a liquidremoval in accordance with the invention between a water bath and aliquid bath containing an extraction liquid, or between a liquid bathcontaining a coating liquid and the subsequent rinsing bath, or even atthe end of the liquid treatment of the contact lenses before the contactlenses are transported to the next processing station, for example to aninspection station.

The invention has been described with a reference to the particularembodiments shown in FIG. 1 to FIG. 6. However, for the skilled personit is evident that many changes and modifications can be made withoutdeparting from the general concept underlying the invention. Therefore,the scope of protection is not intended to be limited to the embodimentsdescribed but rather is defined by the appended claims.

The invention claimed is:
 1. A system for removing a liquid from acontainer (1) for accommodating an ophthalmic lens, the systemcomprising: a transport carrier (12) comprising a container (1) having abottom (11), the bottom having a convex shape, a conveyor (3) fortransporting the transport carrier (12) from a liquid bath (13) to asubsequent processing station (14), an aspirator (2) comprising asuction cup (21) connected to a vacuum supply line (23), for applyingsuction (20) to the bottom (11) of the container (1), a positioner (4)for arranging the container (1) relative to the suction cup (21) suchthat the bottom (11) of the container (1) is exposed to the suction (20)applied by the suction cup (21) during operation, in order to remove theliquid from the container (1); and wherein the suction cup (21) of theaspirator (2) has a concave wall (22) with at least one suction orifice(24) arranged in the concave wall (22), and wherein the convex shape ofthe bottom (11) of the container (1) and the shape of the concave wall(22) of the suction cup correspond to allow for accommodating theconvexly shaped bottom (11) of the container (1) in a cavity bounded bythe concave wall (22) of the suction cup (21); and wherein thepositioner (4) comprises an actuator for linearly moving the suction cup(21) of the aspirator (2) towards and away from the bottom (11) of thecontainer (1).
 2. The system according to claim 1, wherein thepositioner (4) comprises an actuator for linearly moving the suction cup(21) of the aspirator (2) towards and away from the bottom (11) of thecontainer (1).
 3. The system according to claim 1, wherein the actuatoris a pneumatic linear drive.